The nutritional and metabolic mechanisms responsible for life extension in dietary restricted conventional and germfree rats are unknown. Research at Lobund Laboratory at the University of Notre Dame, using the Lobund Wistar (L-W) rat, has shown that ad libitum fed germfree (GF-F) rats live longer than ad libitum fed conventional (CV-F) rats. Rats fed 70% of normal intake (GF-R and CV-R) from weaning age have significantly extended life spans, but the GF rats still live longer. The 50% and maximum survival ages in months respectively for each group are CV-F:22 and 37, CV-R:39 and 42, GF-F:35 and 38 and GF-R:40 and 48. At 30 months of age, 68% of CV-F, 85% of CV-R, 72% of GF-F and 95% of GF-R rats are still alive. Investigators from Lobund Laboratory, Notre Dame, and elsewhere are collaborating to study the aging process in the L-W rat with the goal of integrating their findings into a comprehensive assessment of the mechanisms by which dietary restriction and germfree life may extend life span. Since the experimental phase of this research is now almost complete, we are applying for a Conference Grant from NIA to present the findings of this unique study to other experimental gerontologists. The conference will feature 26 presentatious by the collaborators on their findings as well as comparisons with their own research on other animal models. The topics to be covered are: germfree research, pathology, immunology, bone physiology, endocrinology, gastrointestinal physiology and the biochemistry of aging, In addition, highly qualified experimental geronotologists will be invited to evaluate the findings. The proceedings of the symposium will contribute to the basic understanding of the aging process since the information to be presented has been derived from a multidisciplinary group using the same experimental animal model.